// ATMEGA8 12MHz
#define G0_D       PD6
#define G1_B       PB1
#define G2_B       PB2
#define G3_B       PB5
#define DP_C       PC1 //PD SETKA  

#define E_B        PB3
#define G_B        PB4
#define B_B        PB0
#define F_D        PD7
#define A_D        PD5
#define D_C        PC2
#define C_C        PC3

#define SET        PD0
#define UP         PD1
#define DOWN       PD2

#include <avr/io.h>
#include <util/delay.h>

#define ADDR_DS1307    0b1101000
#define CPU_F          12000000 // Clock Speed 
#define SCL_F          100000 // // I2C Speed

byte a[4],an,segm,i;
int msec,sec,min,hour,set;
int set_sec,set_min,set_hour;
 
int main() {
  TWBR = (((CPU_F)/(SCL_F)-16 )/2) ;
  TWSR = 0;
 // set_time(22,7,2,26,13,10,0);// год 00-99, ДН 1-7 (1=ВС), месяц 1-12, дата 1-31, час 0-23, минуты 0-59, секунды 0-59
  cli();
// (12000000/((18749+1)x64))=10 Hz
  OCR1A = 18749;
  TCCR1B |= (1 << WGM12);
// Prescaler 64
  TCCR1B |= (1 << CS11) | (1 << CS10);
  TIMSK |= (1 << OCIE1A);
// (12000000/((155+1)x256))=300.48076923077 Hz
  OCR2 = 155;
  TCCR2 |= (1 << WGM21); 
// Prescaler 256
  TCCR2 |= (1 << CS22) | (1 << CS21);
  TIMSK |= (1 << OCIE2);
  sei();
  DDRB|=(1<<G1_B)|(1<<G2_B)|(1<<G3_B)|(1<<E_B)|(1<<G_B)|(1<<B_B);
  DDRC|=(1<<D_C)|(1<<C_C)|(1<<DP_C);
  DDRD|=(1<<G0_D)|(1<<F_D)|(1<<A_D);
  PORTD|=(1<<SET)|(1<<UP)|(1<<DOWN);
 
 
while(1) {
   sec =  (i2c_read_1bit(ADDR_DS1307,0) & 0x0F) + (((i2c_read_1bit(ADDR_DS1307,0) & 0x70) >> 4) * 10);
   min =  (i2c_read_1bit(ADDR_DS1307,1) & 0x0F) + (((i2c_read_1bit(ADDR_DS1307,1) & 0x70) >> 4) * 10);
   hour = ((i2c_read_1bit(ADDR_DS1307,2) & 0x0F) + ((i2c_read_1bit(ADDR_DS1307,2) & 0x70) >> 4) * 10);   

   if(((PIND >> SET) & 1) == 0){set++;if(set>3){set=0;}_delay_ms(300);}
   
   set_sec=sec;
   set_min=min;
   set_hour=hour;
   
   if(((PIND >> UP) & 1) == 0 && set==1){set_hour++;if(set_hour>23){set_hour=23;}_delay_ms(300);set_time(255,255,255,255,set_hour,255,255);}
   if(((PIND >> DOWN) & 1) == 0 && set==1){set_hour--;if(set_hour<0){set_hour=0;}_delay_ms(300);set_time(255,255,255,255,set_hour,255,255);}

   if(((PIND >> UP) & 1) == 0 && set==2){set_min++;if(set_min>59){set_min=59;}_delay_ms(300);set_time(255,255,255,255,255,set_min,255);}
   if(((PIND >> DOWN) & 1) == 0 && set==2){set_min--;if(set_min<0){set_min=0;}_delay_ms(300);set_time(255,255,255,255,255,set_min,255);}

   if(((PIND >> UP) & 1) == 0 && set==3){set_sec=0;_delay_ms(300);set_time(255,255,255,255,255,255,set_sec);}
   if(((PIND >> DOWN) & 1) == 0 && set==3){set_sec=0;_delay_ms(300);set_time(255,255,255,255,255,255,set_sec);}

if(set==0){    
   a[3]=hour/10;
   a[2]=hour%10;
   a[1]=min/10;
   a[0]=min%10;
}
   if(set==1&&(msec==0||msec==5)){a[3]=10;}else{a[3]=hour/10;}
   if(set==1&&(msec==0||msec==5)){a[2]=10;}else{a[2]=hour%10;}
   if(set==2&&(msec==0||msec==5)){a[1]=10;}else{a[1]=min/10;}
   if(set==2&&(msec==0||msec==5)){a[0]=10;}else{a[0]=min%10;}
if(set==3){
   if(msec==0||msec==5){a[1]=10;a[3]=10;a[2]=10;}else{a[3]=10;a[2]=10;a[1]=sec/10;}
   if(msec==0||msec==5){a[0]=10;a[3]=10;a[2]=10;}else{a[3]=10;a[2]=10;a[0]=sec%10;}
}
   if(msec<5){PORTC |=(1<<DP_C);}
   if(msec>=5){PORTC &=~(1<<DP_C);}

 _delay_ms(100);
}}
 
ISR(TIMER2_COMP_vect){
    switch(i){
    case 0:  segm=a[0];  an=0;  anod();segment(); break;
    case 1:  segm=a[1];  an=1;  anod();segment(); break;
    case 2:  segm=a[2];  an=2;  anod();segment(); break;
    case 3:  segm=a[3];  an=3;  anod();segment(); break;
    }i++;if(i>3){i=0;}}
 
void segment(){                                                                
   switch(segm){                                                                 
    case 0: PORTD &=~(1<<A_D);PORTB &=~(1<<B_B);PORTC &=~(1<<C_C);PORTC &=~(1<<D_C);PORTB &=~(1<<E_B);PORTD &=~(1<<F_D);PORTB |=(1<<G_B);break;
    case 1: PORTD |=(1<<A_D);PORTB &=~(1<<B_B);PORTC &=~(1<<C_C);PORTC |=(1<<D_C);PORTB |=(1<<E_B);PORTD |=(1<<F_D);PORTB |=(1<<G_B);break; 
    case 2: PORTD &=~(1<<A_D);PORTB &=~(1<<B_B);PORTC |=(1<<C_C);PORTC &=~(1<<D_C);PORTB &=~(1<<E_B);PORTD |=(1<<F_D);PORTB &=~(1<<G_B);break;
    case 3: PORTD &=~(1<<A_D);PORTB &=~(1<<B_B);PORTC &=~(1<<C_C);PORTC &=~(1<<D_C);PORTB |=(1<<E_B);PORTD |=(1<<F_D);PORTB &=~(1<<G_B);break;
    case 4: PORTD |=(1<<A_D);PORTB &=~(1<<B_B);PORTC &=~(1<<C_C);PORTC |=(1<<D_C);PORTB |=(1<<E_B);PORTD &=~(1<<F_D);PORTB &=~(1<<G_B);break;   
    case 5: PORTD &=~(1<<A_D);PORTB |=(1<<B_B);PORTC &=~(1<<C_C);PORTC &=~(1<<D_C);PORTB |=(1<<E_B);PORTD &=~(1<<F_D);PORTB &=~(1<<G_B);break;
    case 6: PORTD &=~(1<<A_D);PORTB |=(1<<B_B);PORTC &=~(1<<C_C);PORTC &=~(1<<D_C);PORTB &=~(1<<E_B);PORTD &=~(1<<F_D);PORTB &=~(1<<G_B);break;
    case 7: PORTD &=~(1<<A_D);PORTB &=~(1<<B_B);PORTC &=~(1<<C_C);PORTC |=(1<<D_C);PORTB |=(1<<E_B);PORTD |=(1<<F_D);PORTB |=(1<<G_B);break;
    case 8: PORTD &=~(1<<A_D);PORTB &=~(1<<B_B);PORTC &=~(1<<C_C);PORTC &=~(1<<D_C);PORTB &=~(1<<E_B);PORTD &=~(1<<F_D);PORTB &=~(1<<G_B);break; 
    case 9: PORTD &=~(1<<A_D);PORTB &=~(1<<B_B);PORTC &=~(1<<C_C);PORTC &=~(1<<D_C);PORTB |=(1<<E_B);PORTD &=~(1<<F_D);PORTB &=~(1<<G_B);break;
    case 10: PORTD |=(1<<A_D);PORTB |=(1<<B_B);PORTC |=(1<<C_C);PORTC |=(1<<D_C);PORTB |=(1<<E_B);PORTD |=(1<<F_D);PORTB |=(1<<G_B);break;
    }}
 
void anod(){
 switch(an){                                                             
    case 0: PORTB |=(1<<G3_B);PORTD &=~(1<<G0_D);break;
    case 1: PORTD |=(1<<G0_D);PORTB &=~(1<<G1_B);break; 
    case 2: PORTB |=(1<<G1_B);PORTB &=~(1<<G2_B);break; 
    case 3: PORTB |=(1<<G2_B);PORTB &=~(1<<G3_B);break;                                                     
    }}   
 
ISR(TIMER1_COMPA_vect){msec++;if(msec>9){msec=0;}}

void set_time(byte years, byte days, byte monts, byte datas, byte hours ,byte minute, byte second){
    if(second < 255){i2c_write(ADDR_DS1307,0x00,(second/10<<4)+second%10);}
    if(minute < 255){i2c_write(ADDR_DS1307,0x01,(minute/10<<4)+minute%10);} 
    if(hours < 255){i2c_write(ADDR_DS1307,0x02,(hours/10<<4)+hours%10);}
    if(days < 255){i2c_write(ADDR_DS1307,0x03,days);}
    if(datas < 255){i2c_write(ADDR_DS1307,0x04,(datas/10<<4)+datas%10);}
    if(monts < 255){i2c_write(ADDR_DS1307,0x05,(monts/10<<4)+monts%10);}
    if(years < 255){i2c_write(ADDR_DS1307,0x06,(years/10<<4)+years%10);}
    }    

void i2c_write(byte i2c_addr, byte i2c_reg, byte i2c_dat){
   TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN);  // START
  while (!(TWCR & (1<<TWINT)));
   TWDR = i2c_addr << 1;
   TWCR = (1<<TWINT) | (1<<TWEN);
  while (!(TWCR & (1<<TWINT)));
   TWDR = i2c_reg;
   TWCR = (1<<TWINT) | (1<<TWEN);
  while (!(TWCR & (1<<TWINT)));
   TWDR = i2c_dat;
   TWCR = (1<<TWINT) | (1<<TWEN);
  while (!(TWCR & (1<<TWINT)));
   TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO); // СТОП
  } 
  
int i2c_read_1bit(byte i2c_addr, byte i2c_reg){
   TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN);  // START
  while (!(TWCR & (1<<TWINT)));
   TWDR = i2c_addr << 1;
   TWCR = (1<<TWINT) | (1<<TWEN);
  while (!(TWCR & (1<<TWINT)));
   TWDR = i2c_reg;
   TWCR = (1<<TWINT) | (1<<TWEN);
  while (!(TWCR & (1<<TWINT)));
 
   TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN);  // START
  while (!(TWCR & (1<<TWINT))); 
   TWDR = (i2c_addr << 1) | 1;
   TWCR = (1<<TWINT) | (1<<TWEN);
  while (!(TWCR & (1<<TWINT)));
 
   TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWEA); 
  while(~TWCR&(1<<TWINT));
    byte i2c_data = TWDR; 
  TWCR = (1<<TWINT) | (1<<TWEN);
  while (!(TWCR & (1<<TWINT)));
 
   TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO); // СТОП
  return i2c_data;
  }